Some electronic devices, such as laptop computers and cellular telephones, may be equipped with an ambient light sensor to support a variety of control functions, such as to adjust keyboard backlighting or display brightness. Some electronic devices may also be equipped with an infrared sensor for receiving infrared signals from, for example, a remote control. Infrared signals intended for the infrared sensor may interfere with operation of the ambient light sensor and cause the device to operate improperly. Thus, an ambient light sensor is needed that can suppress noise from infrared sources.